U.S. Pat. No. 3,224,989 discloses polymerizable long chain fatty oil, fatty acid and fatty acid ester compounds having vicinal acryloxy and hydroxyl groups. Recently, it has been found that such compounds are particularly useful as substituents of so-called "100 percent solids" radiation curable coatings and inks. These coatings and inks, which contain no volatile solvents, are comprised of one or more of the aforesaid compounds, and photoinitiators, and they polymerize upon exposure to radiation to form solid coatings or inks. Such coatings and inks are advantageous to use, since curing them does not require the application of heat and the associated release of volatile solvents into the atmosphere, yet they can be applied to substrates using conventional liquid film application methods. In order to conveniently apply such coatings and inks, it is desirable that all the substituents have relatively stable viscosities. A problem has been observed in the use of certain of the aforesaid vicinal acryloxy hydroxyl compounds in that the viscosities of the compounds have increased during prolonged periods of storage. In particular, vicinal acryloxy hydroxyl derivatives of linseed oil have increased in viscosity by as much as 3,000 to 6,000 cps (measured at 100.degree. F.) after room temperature storage for periods of 1 to 5 months. Such viscosity increases during storage are highly undesirable when the compounds are to be employed in coatings or inks, since they would necessitate viscosity adjustment at the time of use by altering the coating or ink composition, with resultant changes in properties of the composition, or adjustment of coating equipment to account for viscosity variations in the coatings or inks.